Most telephone companies today provide analog telephone and other services to customers using a legacy infrastructure comprising a single twisted pair (TP) of wires for each telephone number. Conventional analog telephone service is often referred to as a plain old telephone service (POTS), and the twisted pair is referred to as a POTS line pair, or simply as a POTS TP. In some instances, it is desirable to locate auxiliary electronic devices or equipment associated with the twisted pair at locations other than either the service provider's central office (CO) or the customer's premises (CP). This is particularly the case where the telephone company offers other types of services to customers, such as broadband data services, e.g., DSL services, where it may be desirable to employ signal processing electronics such as amplifiers, line equalizers, or signal boosters, for instance, at an intermediate location on the TP lines. Providing operating power to such electronics in the field, particularly at remote locations, can be difficult and challenging. If an AC power grid is accessible at the remote location, it may be tapped to provide operating power to the electronics. However, this is not always either convenient or an option. It requires technicians in the field to deal with high voltage wiring, and the power company may not permit technicians other than their own personnel to access the power grid.
Another approach for powering remote devices associated with a first twisted pair of lines is to use one or more other twisted pairs of lines from the central office that are not active, i.e., that are not used for providing voice, data or other services to customers, to carry power to the remote devices. In some cases, multiple lines from the CO may be tied together (bonded) in order to power electronics associated with one active twisted pair. This is disadvantageous since using inactive lines for providing power uses valuable resources, making them otherwise unavailable, may consume large amounts of power, and is otherwise not cost effective.
Another approach, which is also problematic and which generally has been less than successful, attempts to extract power from an active twisted pair of lines to power electronic circuits. The telephone company uses DC and AC currents for line signaling and control of POTS service. Schemes that extract power from the twisted pair can interfere with the normal signaling and control functions provided by these DC and AC currents and disrupt the POTS service or cause other problems on a line. Accordingly, such approaches have been feasible only in limited situations.
There is a need for flexible and convenient approaches for powering remote electronics associated with an active twisted pair of telephone lines that address the foregoing and other disadvantages of known approaches. In particular, it is desirable to provide systems and methods for powering remote electronics from an active twisted pair of telephone lines which is being used by a service provider for providing services to customers without disrupting or interfering with these services, and it is to these ends that the present invention is directed.